Fundamentals of Power Management

Apparent Power is the product of the rms voltage times rms current Apparent Power = E-rms x I-rms <---- also called (VA) The single phase (θ) power factor of a load is a ratio of real or true power (EI cos θ) to the apparent power (EI or volt-amperes). In…

Although all Valhalla wattmeters are compatible with general purpose current transformers, there are distinct accuracy and bandwidth advantages to using a current shunt when making a power measurement. Current shunts generally provide greater accuracy over a broader frequency range than current transformers (CT's). Rather than measure actual in-series current flow,…

For Distorted Waveshapes of All Types The success of the Valhalla 2100 series wattmeter design is centered around a four-quadrant multiplier. The significance of the four quadrant theory is to provide a proper computation for watts under any phase relation between voltage and current to ensure that indeed EI cos…

The AC power drawn from the source (e.g. line - 120VAC @ 60Hz 220VAC @ 50Hz) is the integral over one cycle of the instantaneous watts values. As shown in figure C, during a portion of each cycle power is used by the inductive device (e.g. electric motor), while during…

When describing the amplitudes of electronic devices, terms such as "volts RMS" or "amperes RMS" are used. The RMS (root mean square) of a sine wave produces the same "heating effect" as an equivalent DC voltage level. (i.e. 5 VAC RMS = 5 VDC). Since a given AC RMS amplitude…